This is the dog I'm taking care of while housesitting.  A few minutes after I took this picture, I tried to eat a piece of pizza and he cornered me, barking and staring me down.  I climbed over the ottoman and put the pizza back in the refrigerator.  I tried a couple more times and it was basically the same thing.  After I took the dog for an extra walk, I came back and sat at a high counter to eat my piece of pizza.  It was ok.  My sister said I should let the dog know who's in charge, but I think I already did.  It's clearly him.